Surface gaze format

[papr]

@cboulay I am currently trying to extend the plugin to support surface mapped gaze. But the one channel_format-per-outlet rule is making life difficult for me.

While in a perfect world, every surface would have its own outlet, this is not feasible for the LSL Relay plugin without intertwining it deeply with Capture's Surface Tracker plugin. I thought of building a flexible outlet following the tidy data approach:

LSL timestamp	surface name	norm_pos_x	norm_pos_y	confidence	is on surface
t	Screen left	0.5	0.5	1.0	True
t	Screen right	-1.5	0.5	1.0	False
t+1	Screen left	1.5	0.5	1.0	False
t+1	Screen right	0.5	0.5	1.0	True

As mentioned above, I am not able to mix the string column with the double columns (I think). If I understood the documentation correctly, one should be building time-synced outlets instead. @cboulay Would the following outlet layouts conform to LSL best practices? If not what would you recommend? I am only semi-happy with the solution below.

1. Surface Name outlet (type: string)

LSL Timestamp	Surface ID	Surface Name
t	1.0	Surface left
t	2.0	Surface right
t+1	1.0	Surface left
t+1	2.0	Surface right

Surface ID would correspond to the string representation of the surface id. Surface ids would be incrementing integers in the order of appearance in the processed data.

2. Surface Gaze outlet (type: double)

LSL timestamp	surface id	norm_pos_x	norm_pos_y	confidence	is on surface
t	1.0	0.5	0.5	1.0	1.0
t	2.0	-1.5	0.5	1.0	0.0
t+1	1.0	1.5	0.5	1.0	0.0
t+1	2.0	0.5	0.5	1.0	1.0

[papr]

One alternative would be to use the original single-outlet design with a string format and using either the string representation for the floats or struct.pack. Both do not seem particularly satisfying to me.

[matinpf]

Hi Pablo Prietz,

We are using App-PupilLabs in our research and even your second solution will be great for our goal (because we only have one surface which is a screen).

Could you please help with sharing codes or any implementation hints?

[mitchellsayer]

@papr Did you ever get this working?